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Optical properties of a Tm-doped LaF 3 single crystal have been detailed investigated as a promising material for ∼1.84 μm lasers for the first time. Judd-Ofelt theory was applied to analyze the absorption spectrum. With the J-O intensity parameters Ω t ( t = 2 , 4 , 6 ) , the emission probabilities, branching ratios and radiative lifetimes for the as-grown crystal were all calculated. The stimulated emission cross-section of the 3 F 4 → 3 H 6 transition was obtained by using the Fuchtbauer-Ladenburg method. The gain cross-section for ∼1.84 μm emission becomes positive once the population inversion level reaches 30%. The fluorescence lifetime of the 3 F 4 manifold was measured to be 15.56 ms. Potential utility of the Tm:LaF 3 crystal as laser active material at ∼1.84 μm can be expected. [ABSTRACT FROM AUTHOR]

Optical properties of a Ho-doped LaF 3 single crystal have been detailed investigated as a promising material for 2 μm and 2.9 μm lasers for the first time. Judd–Ofelt theory was applied to analyze the absorption spectrum to determine the J–O intensity parameters Ω t ( t =2,4,6) , based on which the emission probabilities, branching ratio and radiative lifetime for the as-grown crystal were all calculated. The stimulated emission cross-sections of the 5 I 7 → 5 I 8 and 5 I 6 → 5 I 7 transitions were obtained by using the Fuchtbauer–Ladenburg method. The gain cross-section for 2 μm emission becomes positive once the population inversion level reaches 30%. The Ho:LaF 3 crystal shows long fluorescence lifetime of 5 I 7 manifold (25.81 ms) as well as 5 I 6 manifold (10.37 ms) compared with other Ho 3+ -doped crystals. It can be proposed that the Ho:LaF 3 crystal may be a promising material for 2 μm and 2.9 μm laser applications. [ABSTRACT FROM AUTHOR]

A Dy:LaF 3 crystal was grown successfully by the Bridgman method, and X-ray diffraction results show that it is well-crystallized. The room temperature absorption spectra, fluorescence spectra and the fluorescence decay curves were measured. On the basis of J-O theory, the emission probabilities, branching ratios, and the radiation lifetimes of the 4 F 9/2 and 6 H 13/2 manifolds were calculated. The stimulated emission cross-sections of the 4 F 9/2  →  6 H 13/2 transition (∼570 nm) and the 6 H 13/2  →  6 H 15/2 transition (∼2.86  μ m ) were obtained by the Fuchtbauer–Ladenburg equation. The fluorescence lifetime of the 4 F 9/2 and 6 H 13/2 manifolds are 1.37 ms and 9.73 ms, respectively. All these results were first investigated, indicating the Dy:LaF 3 crystal a promising material for 570 nm and 2.86  μ m laser applications. [ABSTRACT FROM AUTHOR]